4 - 5
Pin
Port
Description
number
name
Pin
Port
Description
number
name
1
2
3
5
6
7
8
16
17
18
20
21
22
23
27
28
29
31
83
84
88
89
90
91
CONT1
CONT2
BEEP
CH16
CHWX
H/L
DSDEC
PCK
PSTB
PDATA
ICFC
BPLVL
ECK
EDA
HI/LO
RRXD
RRXD
BPFV
TMUT
NMEAI
WXDEC
SQLV
SQL
LBAT
Outputs control signal for the LCD
contrast.
Outputs beep audio signal.
Input port for the CH16 switch.
Low: While CH16 switch is pushed.
Input port for the CHWX switch.
Low: While CHWX switch is pushed.
Input port for the H/L switch.
Low: While H/L switch is pushed.
Input port for ATIS/DSC decode sig-
nal.
Outputs clock signal to the PLL IC
(MAIN unit; IC2, pin 4).
Outputs strobe signals to the PLL IC
(MAIN unit; IC2, pin 3).
Outputs data signals to the PLL IC
(MAIN unit; IC2, pin 5).
Outputs control signal to swtich NMEA
or ICF3 (Optional unit; HM-127).
Outputs beep volume control signal.
Low: Beep audio is maximum.
Outputs clock signal for the EEPROM
(IC2, pin 6).
I/O port for the EEPROM data signals.
Output port for RF output power (High
or Low) select signal.
Input port for the communication data
from HM-127.
Outputs communication data to HM-
127.
Outputs bandpass filter select signals.
Low: Receiving more than 160 MHz.
High: Receiving less than 160 MHz.
Outputs transmit mute signal.
High: While transmitting.
Input port for GGA and NMEA data.
Input port for WX alert signal.
Input port for the squelch volume
level.
Input port from the FM IF IC (MAIN
unit; IC1) for the squelch operation.
Input port for the connected power
supply voltage detection (low battery
indicator).
92
93
94
95
96
97
98
99
Input port for TX LED control signal.
Input port for the smart mic functions.
2.02 V: [UP] is pushed.
3.00 V: [DN]] is pushed.
3.84 V: [16/9] is pushed.
Input port for the PTT switch from HM-
129.
Low: While PTT is pushed.
Input port for the DTRS switch.
Low: While DISTRESS switch is
pushed.
Input port for the DSC switch.
Low: While DSC switch is pushed.
Input port for the UP switch.
Low: While UP switch is pushed.
Input port for the DOWN switch.
Low: While DOWN switch is pushed.
Input port for the PLL unlock signal.
Low: While PLL is locked.
TXDET
KEYM
PTT
DTRS
DSC
UP
DOWN
UNLK
4-7 PORT ALLOCATIONS
4-7-1 CPU (LOGIC BOARD; IC1)
CONT1
0
1
CONT2
0
1
CONTRAST
LIGHT
DEEP
Pin
Port
Description
number
name
4
5
6
7
11
12
13
14
RMUTM
RMUTS
PTTM
PTTS
MMUTE
SMUTE
SEND
RCV
Outputs the AF mute swtich (MAIN
unit; IC5) control signal for main body.
Low: While squelched
Outputs the AF mute swtich (MAIN
unit; IC5) control signal for the option-
al remote microphone (HM-127).
Low: While squelched
Outputs main microphone (HM-129)
select signal to the analog swtich
(IC4) while intercom operation.
Outputs optional microphone (HM-
127) select signal to the analog swtich
(IC4) while intercom operation.
Outputs select signal for the speaker
of the main microphone (HM-129) to
the analog swtich (IC5) while intercom
operation.
Outputs select signal for the speaker
of the optional microphone (HM-127)
to the analog swtich (IC5) while inter-
com operation.
Outputs the T5 regulator (MAIN unit;
Q24, Q25) control signal.
High: While transmitting
Outputs the R5 regulator (MAIN unit;
Q22, Q23) control signal.
High: While receiving.
4-7-2 I/O EXPANDER IC (LOGIC BOARD; IC3)
